Shaft-driving mechanism



Aug. 17 19255e W. O. BENTLEY ET AL SHAFT' DRIVING MECHANISM Filed August 13. 1923 5 Sheets-Sheet 1 1,596,332 w, Q. EEMTLEY ET AL SHAFT DRIVING MECHNISM Agg. 17 ,@1926n 'Filed August 13, 1923 3 Sheets-Sheet 2 Aug. 1.7 192e. 1,596,332

W. O. BENTLEY ET AL SHAFT DRIVING -MECHANISM Filed August 1:5, 1923' s sheets-sheet s v Imre/7 fors QM@ ffQW Patented Aug. 17, 1926.

UNITED rammenta rentrer am) menester Tzrsksnjsenenss, 'or tonnen, seaman.

1,596,332 lenteur osi-frcs;

snaar-esserne meenemen.

Apenas-nen mea August 113., 1923, sensu ne. esta-13, and infereat nfaii December 21, ma

This invention relates to tshaft drivinz mechanism, and is mainly intended 'for use on internal combustion engines for operating overhead cam shafts thereon. The type of mechanismris that in which two or more cranks or ec'centrics spaced around the 'drivingshaft are severally connected Vby hinged lin-ks With ak corresponding plurality of cranks Ior eccentrics around the 'driven shaft, and the principal` object of the invention is to provide a simple and silent form 'ofdrive wherein the 'effect of cylinder 'expansion in altering the distance apart 'of the driving and driven shafts is automatically compensated. A further 'object is to provide in a simple manner for the accurate adjustment of the links With a view to avoiding any binding action in the drive.

According to this invention, "each link comprises two telescopic or equivalently connected Yparts which are provided 'with means, resilient or 'otherwise 'and preferably adjustable, for limiting their movement toivadis and/or away from Ione another. Thus there /l may be simply 'an 'adjustable abutment upon Y the one engageable by a cef-operating surface upon the other, so that the drive isy transmitted merely by a push-ing aetion of eaeh link, or combined With this there may i be a spring which tends to' extend the link during-its idle movement and avoids shock upon the abutment when the extension is] again taken up by the drive. In each Vcase provision is made for a.A Change in the 'dis-` expansion or other enects. Y

Alternatively the extension and ycontraction of the link can be yie'ldingly resisted inV both directions by springs, 'dashpots or equivalent devices, preferablyV with means foradjusting their loadings..Y

lfh'e manner of carrying out the invention is illustrated in the 'accompanying drawings, inrtvhi'ch v 'l `Figure 1 is a part-sectional elevation of one` construction, i

Figure 2 is a part 'sectional elevation of a modified construction,

Figure 3 is an 'elevation of a furtherl modi-- tance v'apart of lthe shafts arising through fication lcombining certain of the features shown in both Figures l 2,

Figure i is a sectional elevation of a part of the link with certain features applicable to the Constr-netten shown in beth Figures l and 3,

ythreaded to receive 'the nuts VA5 Figure 5 xisi-a part-sectional elevation 'of a further modification, and

`Figure 6 is :a 'diagrammatic illustration viceversa) and eachcarries cranks for eccen'- i trios F2 and G2 coupled together by links,

so that the. rotary motion of one shaft'is Atransmitted to the other in the Well-known manner.v lV-h'ere the driven shaft is a camshaft Which rotates at half the speed of the engine crankshaft, the driving shaft F would be geared to the crankshaft by toothed gearing of the corresponding ratio.

' V-I-n the construction shown by-Figure l,

each link is constitutedby a pair' 'of reds ,A., A2arranged side by side, and at one end extending through the two ,parts B, B2 of a divided bearing forming one eye of the link and constituting --for lthis thee-connect- :ing bolts, the rods beingr providedW-ith shoulders A3 and their eXtrem-Ines'A4t being tighten the'pa'rts of the hearing up against the 'shoulders A At the opposite end a similar ypair of bearings C, C2y constitute the other eye of the link, `but these are slida-bly mounted upon the tvvo rods A, A2 lto allow/ for their free-l dom of movemennand also for their initial adjustment astothe distance apart ofthe eyes ofthe link. @n each side l'of the sliding Abearings coil springs D, D2`are mounted 'upon the rods and are located in each'case between the bearing and, fixed and adjustable ah'ut'ments respectively, such as the collars E and the nuts E2 screw-threaded upon 'the rods A, A2. It Will be* evident, therefore, that by adjusting these nuts E2 along the rods,-the link can be brought to the dcsiredv effective length, While at the sam-e time the springs D, D2 will be given their 'appropriate loading. Any suitable means are employed to lock the nuts E2 after adjustment, andthe normal length of the links can be readily checked in the-first instance by means vof a jig.-

which y By the foregoing'arrangementit Will be i seen that the link is both resiliently ez'- ftensible and compressible, so that a veryV the member H2.

smooth drive is transmitted and any change in the distance apart of the centres of the driving and driven shafts (indicated respectively by F and G, with cranks F2, G2) through expansion or other causes which arise in the driving of an overhead camshaft of an internal combustion engine is automatically met by a change in the length of the link, so that binding 'in the drive is avoided.

To minimize weight, the two rods A, A2 are of relatively small diameter, and to avoid their buckling under a compressive load they' may be stiffened and tied to one another by ties such as A6.

In a more elaborate method of carrying out the invention illustrated by Figure 2, the link is telescopic, comprising two members H, H2 (the inner preferably tubular as well as the outer) sliding one within the other, and each at its outer end provided with a bearing or eye to engage respectively With the cranks F2, G2. Preferably the tubular rods are 'ended as at H3, H4, so as to have attached to them, divided bearings J, J2 forming the eyes and secured by a pair of bolts J 2 spaced apart in the known manner, thereby providing a sound mechanical construction.

The T-end portion H3 for the inner meinber H2 of the link is preferably formed separately and is attached by providing in it a screw-threaded socket H5 engaged by a correspondingly screw-thread end of a reduced part H6 on the member H2. This reduction is made for a considerable distance beyond the end of the socket H5 and provides for the mounting upon the reduced part of a compression spring K before the T part is attached. This compression spring is located within the outer tubular member H, the mouth of which is counterbored at H7 for the reception of a threaded sleeve L forming an adjusting nut which is adapted to bear upon the end of the spring K to thrust it against the shoulder H8 formed by reducing Between the inner end H" of the member H2 and the inner end H10 of the tubular member in which it slides is located another compression spring K2, preferlably of similar diameter and strength to the spring K. It will be evident, therefore, that when the adjusting sleeve nut L is screwed up it will bear against the spring K, which in turn bears against the shoulder H8 formed by reducing the inner rod, and thisrlatter, therefore, will be thrust down against the spring K2 bearing against the inner ends of the outer rod. Thus the two springs K, K2, will act in opposition to one another with equal and opposite forces which tend to resist either extension or contraction of the link. A locking nut L2 may be provided to lock the adjusting sleeve nut L, and the lat.- ter may have a tubular portion L2 which eX- tends in the opposite direction to its threaded part to embrace the outside of the socket H5, thereby to vstiften the joint.

It will be seen that with the latter arrangement, only two springs are required for each link as against four for the first described construction, and a compact and simple method of adjusting the distance apart of the centres of the link is provided. It will also be seen that in an adjustment of this nature the load upon the springs will be equalized, and a resilient push and pull will result in the driving action.

The first described construction, however, besides being light is relatively inexpensive to manufacture, while all the springs are visible so that the degree of their loading and the amount by which they can yield without becoming solid is readily ascertained. Tn the second construction, only half the number of springs employed in the first mentioned is required, but they are not visible. The construction, however, is of a much more substantial nature.

In the construction shown by Figure 3, certain of the features shown in Figures l and 2 respectively are combined, and for convenience, therefore, similar reference letters are employed for the like parts. Telescopic members H, H2 with T-ends H2, H4 carry the bearings J and J2. The member H has an additional T-end H11 atthe end opposite to H4, and through this extend thel bolts J4 which serve to connect the bearing J2 to the -end H2. Between the T-ends H3 and H11 are located compression springs J5,

Vand similar compression springs J4 are employed on the other side of the bearing J 2', all arranged upon the bolts J4, so that a resilient push and pull effect is obtained in the drive, and by tightening up the nuts J 7 upon these bolts the springs J 5 and J 6 are loaded and the effective length of the link is adjusted.

TWhere the connecting links are arranged with the bearings slidably mounted upon the two rods, as shown in Figure 1, or upon the bolts J4 in Figure 3, it may be desirable to provide a braking action to damp the movements of the sliding parts. Figure 4 shows the braking device applied to the construction illustrated by Figure l. the bearings C, C2, through which the rods A, A2 extend, are each bushed from opposite ends with a split sleeve M having a conical exterior surface engaging a correspondingly coned hole in the bearings. The springs D, D2 would bear upon the large ends M2 of these coned bushes tending to thrust them into the holes provided for them, so that thereby they are contracted at the split M3 and grip the rods A, A2 upon which they slide, thereby exerting a braking action upon the sliding movements of the bearings upon the rods. The effect, therefore, is that of a The holes in shock absorber With an automatic damp-ing action adapted to eliminate any tendency to rattle if Wear develops in the bearing surfaces. w Y

lt will be evident, therefore, that by the foregoing arrangement, even if thesprings were compressed so tightly as to give a substantially solid drive under Working conditions, the sliding effect for adjustment of the length of theA linkcou'ld still take pla-ce under a heavy load, such as might arise through expansion effects inalteri'ng the distance yapart of the driving and driven shafts, and none the less, therefore, VWhile obtaining Vthe advantages of the automatic adjustnient in length, the conditions Would resemble that of `a solid drive.

links are adapted to exert-both a push and a vpull in the transmission of the drive, it will be evident that as few as tivo cranks or eccentri'cs With their associatedV connecting links maybe employed to constitute. the driving connection, the cranks preferably being arranged at rightl angles to oneanother.

ln the modified con-struction illustrated byr (l2 adapted to bear against the end N?1 of 'the part l of the link Within Which it slides.

sl ltly thickenedy at the end to form an `nent having'a suitable amount of surface to take the thrust which is transmitted throughthe link.

'With the fore-going arrangement, it Will be evident that the effective length of the link can readily be adjusted by means ofthe aforesaid nut or nuts, and if the. link is appropriately adjusted When the engine is cold, any movement apart of the shaft centres when the engine heats up Will be compensated by a corresponding extension in the link at the telescopic joint.

To avoid any shock between the nutO and the adjacent end N4 forming the iiXed abutment on the part N, it is preferred to provide a compression spring between the tvvo` parts of the link, thereby resiliently to thrust the tvvo parts of the link apart, thus taking up all slack arising from clearance caused by expansion or the likeI and ensuring smoothness in driving. A preferred arrangement is to locate the spring P Within the inner end of the part N, so that the adj a cent end of the part N2 can bear against it.

view-ofthe fact tha'tvthe connectingl lf preferred tiis part of the link may be' VViftl-i .a view to set-ting the adjustable abutment in such manner that the effective length of each ofthe links is alike., means may be provided for temporarily locking the cam shaft and the driving shaft in fixed angular relationship With one another during srch adjustment. This may be effected by providing a notch. in the 'drivin-g and the driven shafts, preferably in the 'periphery of a disc provided on each, and employing a detent, which maybe a sliding plunger in each case, to engage the notch in the disc. Thus these plnngers Would be mounted on a fixed part adjacent each shaft, and'vvhen moved axially would engage the shaft in such manner as to lock it. The shafts would thus .be held firmly in their correctangular relationship With one another, and each of the links lcould then be adjusted for effective length in such manner lthat they wouldV all be alike. Obviously such adjustment could be best effected When the line of the link is at rightane'les to the cranks which it couples, and if desired, as many notches might be provided around the disc as there were cranks employed, so that each link could then be brought into the most favourable position for adjustment.

By a suitable modification ofthe telescopic` construction of the link, the interior of the outer vtubular rod may constitute the cylinder 'of a iiuid dashpot, as shown in Figure 6, Where theinner rod Q2 is provided With a piston Q3 which slides freely Within the part Q, of the link and is acted upon on both sides by fluid (preferably oil) pressure. thereby progressively to vary its resistance to` extension or compression.

"ln either of the foregoing constructions,'

itivill'be seen that the invention provides notv only for 'changes ofvcentres of the driving and the driven shafts, but ensures Ythat the drive transmitted by the links will be of a resilient nature andcapable of exerting both a push and a pull, or a push only, in the drive. The mechanism of the link is of simple and effective nature and can easily be assembled.

The' invention constitutes also an ineX- pensive form of driving mechanism for tvvo shafts which rotate at similar speeds, and it will be evident that as the effective length of thelink is a matter of adjustment, the parts of the link can bemanufactured so as to suit engines in Which variations exist in the distance apart of the driving and driven shafts.

What We claim as our invention and desire to secure by Letters Patent of the United States is :e

l. In a shaft driving mechanism, the combination of a driving shaft, a driven shaft, cranks spaced around said driving shaft, cranks spaced similarly around said driven shaft, links connecting said cranks ofd the one shaft with corresponding cranks of the other shaft, mechanism compensating for changes in distance between driving and driven shafts comprising a joint in each of said links permitting an automatic alteration in its effective length, and means for limiting the extent of such alteration, substantially as set forth.

2. n a shaft driving mechanism, the com bination of a driving shaft, a driven shaft, cranks spaced around said driving shaft, cranks spaced similarly around said driven shaft, links connecting said cranks of the one shaft with corresponding cranks of the other shaft, mechanism compensating` for changes in distance between driving and driven shafts comprising a joint in each of said links permitting an alteration in its effective length while in motion, and means adapted yieldingly to resist such alteration in length, substantially as set forth.

3. ln a shaft driving mechanism, the combination of a driving shaft, a driven shaft, cranks spaced around said driving shaft, cranks spaced similarly7 around said driven shaft, links connecting said cranks of the one shaft with corresponding cranks of the other shaft, mechanism compensating for changes in distance between driving and driven shafts comprising a joint in each of said links, constituted by forming it of two parts which slidably engage one another thereby to permit an automatic alteration in the. effective length of said link, and means adapted yieldingly to limit such alteration in length, substantially as set forth.

l. In a shaft driving mechanism, the combination of a driving shaft, a driven shaft, cranks spaced around said driving shaft, cranks spaced similarly around said driven shaft, links connecting said cranks of the one shaft with corresponding cranks of the other shaft, mechanism compensating for changes in distance between driving and driven shafts comprising a joint in each of said links, constituted by forming it of two parts which slidably engage one another thereby to permit an alteration in the effective length of said link while in motion, means adapted yieldingly to limit such alteration in length, and a braking device acting upon said sliding parts, the loading of which is increased by the axial load upon the link, substantially as set forth.

5. In a shaft driving mechanism, the combination of a driving shaft, a driven shaft,

cranks spaced around said driving shaft, cranks spaced similarly around said driven shaft, links connecting said cranks of the one shaft with corresponding cranks of the other shaft, mechanism compensating for changes in distance between driving and driven shafts comprising a joint in each of said links permitting an alteration in its effective length, and means for limiting the extent of such alteration comprising coil springs resiliently opposing alteration in each direction, and positively limiting alteration beyond a predetermined extent by the springs becoming solid.

6. In a shaft driving mechanism, a driving shaft, a driven shaft, cranks spaced around said driving shaft, cranks spaced around said driven shaft, links connecting the cranks of one shaft with corresponding cranks of the other shaft and mechanism operatively connected to each of said links to automatically alter its length in compensation for changes in distance between the driving and driven shafts.

In testimony whereof we have signed our names 'to this specification.

WALTER OVEN BENTLEY.

FREDERICK TASKER BURGESS. 

